Field of the Invention
The invention lies in the field of electrical engineering. More specifically, the invention relates to an electricity meter having signal channels which are passed to a digital signal processing device and each of which has an analog/digital converter. Voltage signals of an electrical consumer, which are detected by means of transformers, can thereby be connected to a first input of the analog/digital converter of a first signal channel, and current signals of an electrical consumer, which are detected by means of transformers, can be connected to a first input of the analog/digital converter of the second signal channel. In this context, the term current signals also refers to voltage signals that are proportional to the respective currents. Such an electricity meter is described, for example, in my earlier German patent DE 195 26 723 C1. In that electricity meter, which is designed for a high level of self-monitoring of its measurement or signal channels, the signals which are associated with the respective different signal channels are used to form comparison values. This allows a plausibility check to be carried out on the detected measured values or signals. In this way, it is possible, for example, to find out whether an internal or external fault is present, in which case logic operations in the digital signal processing device may allow the fault to be traced in more detail, or localized.
German patent DE 740 487 C discloses a rotary current three-phase meter which, by using an Aron (two-wattmeter) circuit, can be used for three-conductor and four-conductor connection.